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De Jonckheere JF 《Protist》2004,155(1):89-103
To investigate the variability within species of the genus Naegleria, the ITS1,5.8S and ITS2 rDNA were sequenced of several strains of N. lovaniensis and its Western Australian variants, N. australiensis, N. fowleri, N. andersoni, N. jamiesoni, N. tihangensis, N. pringsheimi, N. pagei, N. gruberi sensu lato and a Naegleria lineage that lost a group I intron from the SSUrDNA twintron. As a result, it is possible to define a molecular species within the Naegleria genus. In addition, one strain of each different allozyme cluster was sequenced to investigate whether they belong to described species or should be treated as distinct new species. This leads to the proposal of eleven new species. The sequencing results from those Naegleria spp. of which several strains are available indicate that these species are ubiquitous. The only exception might be the species represented by the WA variants. However, there are still many Naegleria spp. for which only one strain has been isolated, hence, it is important that the search for more isolates should be continued worldwide.  相似文献   

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Heterotrophic chrysomonads of the genus Paraphysomonas are ubiquitous phagotrophs with diverse silica scale morphology. Over 50 named species have been described by electron microscopy from uncultured environmental samples. Sequence data exist for very few, but the literature reveals misidentification or lumping of most previously sequenced. For critically integrating scale and sequence data, 59 clonal cultures were studied light microscopically, by sequencing 18S ribosomal DNA, and recording scale morphology by transmission electron microscopy. We found strong congruence between variations in scale morphology and rDNA sequences, and unexpectedly deep genetic diversity. We now restrict Paraphysomonas to species with nail-like spine scales, establishing 23 new species and eight subspecies (Paraphysomonadidae). Species having base-plates with dense margins form three distinct subclades; those with a simple margin only two. We move 29 former Paraphysomonas species with basket scales into a new genus, Clathromonas, and describe two new species. Clathromonas belongs to a very distinct rDNA clade (Clathromonadidae fam. n.), possibly distantly sister to Paraphysomonas. Molecular and morphological data are mutually reinforcing; both are needed for evaluating paraphysomonad diversity and confirm excessive past lumping. Former Paraphysomonas species with neither nail-like nor basket scales are here excluded from Paraphysomonas and will be assigned to new genera elsewhere.  相似文献   

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A new heliozoan, Microheliella maris, has sufficiently distinctive ultrastructure to merit a new order, Microhelida. Its 18S and 28S rRNA genes were sequenced earlier under the informal name 'marine microheliozoan'; we here sequenced its Hsp90 gene. A three-gene tree suggests that it is distantly related to centrohelids and others in chromist subkingdom Hacrobia; but it is too divergent to be placed accurately by few genes. Unlike centrohelids, its central spherical centrosome has two concentric granular shells and a dense core devoid of a trilaminar central disc. Microtubules radiate from the centrosomal shells. Unlike centrohelids, axopodia have only three microtubules, fixed basally by dense plasma membrane anchors, and bear terminal and lateral haptosome-like extrusomes. As in the heliomonad Heliomorpha, the centrosome is embedded in a nuclear cavity, and centrosomal microtubules traverse the nucleus inside cytoplasmic channels. A novel filogranular network interconnects mitochondria, ER, and plasma membrane. The microbody is attached to the nucleus and mitochondrion, which has vermicular tubular cristae. We group Microhelida and Heliomonadida, purged of dissimilar flagellates, as a new tubulicristate class Endohelea within phylum Heliozoa. Previously misassigned GenBank 18S rDNA sequences reveal Microhelida as diverse and ancient. We discuss principles underlying the biogenesis and diversity of axopodial patterns.  相似文献   

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The supply of energy, and the frequency of disturbance can both affect species diversity, often, although not always, producing unimodal diversity patterns along an energy or disturbance gradient. However, it has been suggested that diversity is a combined function of both factors, and the dynamic equilibrium model proposed by Huston (1979) is one formalization of this suggestion. This idea has received little direct testing. Here we carry out such a test using protist microcosms, in a factorial manipulation of six levels of energy (quantity of organic resource) and five levels of disturbance (frequency of temperature shock). Species richness responded to both energy supply and disturbance frequency, although not always unimodally. Patterns of response changed over time, and there was some evidence of an interaction between energy and disturbance at two of six time intervals. However, the specific form of this interaction differs from that predicted by the dynamic equilibrium model, and overall, the results provide little support for the model.  相似文献   

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Asahinia kurodakensis is shown to be conspecific with A. scholanderi. Cetraria saviczii var. Candida and A. culbersoniorum (nom. inval.), are only chemical strain of A. chrysantha , lacking usnic acid.  相似文献   

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It has been found that the type species, T. colliculosa, of the form genus Torulopsis constitutes a perfect state forming ascospores. It is proposed that the same “Torulopsis Lodder et Kreger-Van Rij” based on a new type, be conserved against the earlier homonym “Torulopsis Berlese” which is based on the type T. rosea.  相似文献   

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Karyotypes from 72-hour whole blood cultures were compared for six species of macaques (Macaca arctoides, M. fascicularis, M. mulatta, M. nemestrina, M. nigra, and M. radiata) and one species of mangabey (Cercocebus atys). G-bands, sequential C-bands, and late replication patterns were studied. Results showed a variation in a single chromosome pair which differentiated C. atys from the macaques. Heteromorphic variation in silver stained nucleolar organizing regions was seen between and within individuals. This data supports previous work showing the highly conserved nature of the chromosomes of the subfamily Cercopithecus.  相似文献   

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郭英兰 《菌物学报》2013,32(Z1):133-135
报道生于蓼属Polygonum sp.植物上的假尾孢属1个新种:余氏假尾孢Pseudocercospora yui Y.L.Guo.文中提供了新种的拉丁文简介、形态描述、绘图及讨论.模式标本保存在中国科学院微生物研究所菌物标本馆(HMAS).  相似文献   

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邹晓  陈万浩  韩燕峰  梁宗琦 《菌物学报》2016,(10):1161-1168
描述了采自湖北省神农架的球束梗孢属一新种,神农架球束梗孢Gibellula shennongjiaensis,该菌分生孢子梗表面粗糙,瓶梗为棒状,5.4–10.8×1.1–2.2μm。分生孢子为圆柱形或纺锤形,透明,表面光滑,3.2–6.5×1.1–1.6μm。具糙梗孢式共无性型的产孢结构,其分生孢子梗由不规则的菌丝组成,产孢细胞不规则形状,分生孢子无色,光滑,线形,12.1–15.2×1.4–2.1μm。模式标本保存在贵州大学菌种保藏中心(GZAC-SNJ2012,主模式)。  相似文献   

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Ionaspis fuegensis, I. granvina and I. ventosa are described. The genus is recorded for the first time with certainty from the cool-temperate Southern Hemisphere. I. granvina differs from all other species in its carbonaceous black exciple and I. ventosa in its ecology: windswept mountain summits.  相似文献   

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